You should now be able to choose between regular (latin) input and Chinese characters using Ctrl+Space.

To make ibus-daemon start with gnome, rungnome-session-properties
and addibus-daemon
And you're more or less done.

Sogou is a popular pinyin database on the Windows platform -- but afaik it's not available for Linux. On Linux, it seems that the ibus-pinyin-db-open-phrase database is the default ibus database used to guess what characters you intend to type, but you can also install and select either ibus-googlepinyinoribus-pinyin-db-android. After installation you need to select the database by going to preferences in the ibus daemon and selecting it as input method. Not being Chinese I can't tell whether sogou, google pinyin and android pinyin are comparable.
Sogou does however work with Google Chrome/Chromium on linux -- go to Preferences/Extensions -- Get More Extensions, and install the Sogou Cloud Pinyin Extension for Chrome.